The present invention relates to a method for transmitting traffic information, in particular a position of a traffic obstruction on a traffic, in digital coded messages.
For coding and decoding of the messages, location data banks are utilized at transmitters and receivers, and a rough position of the traffic information is coded by referencing to a traffic way and at least one location which is contained in the location data banks and located on the traffic way.
The transmission of digitally coded traffic massages, in particular of TMC (Traffic Message Channel) messages which are coded in accordance with the ALERT-C-protocol and decoded, is supported on the location, which is performed both at the side of the transmitter and also the side of the receiver in connection with traffic ways in location date banks. These locations are traffic-relevant points, such as for example departures and intersections, which are referenced with one another in form of a precursor and successor and to associated street segments, wherein the associated street segment is a part of the street.
By limiting to these traffic-relevant points, the range of the location list is minimized. Simultaneously however a complete description of the traffic way network, in particular a street network is not possible. The description of the roadways is relatively complete. However, for the subordinate street classes, one or several not coded knot points are located between two coded locations. Since in TMC messages only one location code is transmitted per message (primary location), to which the obstruction relates, and a measure which indicates how many coded locations are on one section pertains to the obstruction, both the beginning and the end of the obstruction is transmitted only in form of coded locations (primary and secondary locations). Since the number of the coded locations at the subordinate street classes is low, the precision of the location indication is here not satisfactory, since between the primary and the secondary location as a rule several intersections with other streets are located, which can be used by a navigation system for detouring of the obstruction.